1. Field
One or more embodiments relate to technology for estimating a camera motion in real time.
2. Description of the Related Art
Augmented reality corresponds to technology that may overlappingly exhibit a virtual object in a real world. In general, the real world may use an image captured with a video camera and the like. To overlappingly express a virtual object in a video image without psycho-visual difference, the virtual object may be matched, that is, registered at the same viewpoint as the video image. Every time the video camera moves, a direction and a position of the virtual object may need to be updated. For the above operation, the direction and the position of the video camera may need to be known in real time.
A conventional method of estimating a camera motion, for example, a direction and a position of a camera may generally target an image (hereinafter, a color image) output from a camera sensor configured to sense a strength signal with respect to the wavelength of light. To estimate a camera motion for each frame, a scheme of extracting, from a color image, a set of feature components, for example, a set of points and a set of lines, and comparing and calculating within-color image position information of feature components in an adjacent frame may be employed. In this instance, since a point or a line distinguishingly different from a neighboring pixel value is extracted to extract a feature component, a color value or an intensity value of each pixel may be used.
According to conventional technologies, it may be presumed that the same point in a three-dimensional (3D) space has the same color value or a similar color value for each frame. Accordingly, when an illumination environment significantly varies, a feature component extracted from a previous frame may not be extracted from a current frame. Since a characteristic of a descriptor describing the feature component varies, two feature components may not accurately match. Specifically, it may be highly probable that the estimation of a camera motion may fail. In addition, when a number of feature pixels distinguishable from neighboring pixels is small due to, for example, iteration of similar pattern texture, an area including the same color, and the like, it may be difficult to estimate a camera motion.